With both of my origins, a .22 and a .25 i find no profit in charging above 3000 psi. Every gun is different in terms of turns on the striker spring but my .22 likes three turns out 3000 to 2000 psi with 14.3 gr pellets avg 955 fps, twenty shots. The .25 likes four turns out , 3000 to 2000 psi with 28 gr pellets avg 895 fps, sixteen shots.